Tube expander with hammer action



March 18, 1958 5. J. KAY 2,827,102

TUBE EXPANDER WITH HAMMER ACTION Filed Sept. '7, 1954 34 INVENTOR. 5rmvuri lfiw United States Patent Q TUBE EXPANDER Wrrn HAMMER AcrroNStanley J. Kay, Dearborn, Mich, assignor, by mesne assignments, toAmerican Radiator & Standard Sanitary Corporation, New York, N. Y., acorporation of Delaware Application September 7, 1954, scrim No. 454,483

1 Claim. (Cl. 153-405) The present invention relates to a tube expanderwhich is particularly but not exclusively adapted to be used with heatexchange tubes of the type that are normally encased in fins or baflles.

A problem exists in etficiently afiixing fins to heat exchange tubes foritems such as heaters or air conditioning units. Such fins are providedto obtain the maximum benefit from the heat exchange tubes, particularlyin the situation where a fan or blower moves air over such tubes.

it is preferable to provide a heat exchange member from as few separatelengths of tube as possible in order to reduce the number of couplingsrequired and the overall cost. The tool of the present invention permitsthe use of curved lengths of tube so that the number of separate tubesections required is minimized.

It is a principal object of the present invention to provide a tubeexpanding tool which is simple and economical to make and easy tomaintain.

It is another object of the present invention to provide a tubeexpanding tool which may be etficiently used with a curved length oftube.

It is a further object of the present invention to provide a tubeexpanding tool which is rapid and easy to use.

Other objects of this invention will appear in the following descriptionand appended claim, reference being had to the accompanying drawingsforming a part of this specification wherein like reference charactersdesignate corresponding parts in the several views.

In the drawings:

Fig. 1 is a front elevation of a heat exchange unit of the type withwhich the tube expanding tool of the present invention is used.

Fig. 2 is a fragmentary section of a tube and fin showing the tubeexpanding tool of the present invention in use.

Fig. 3 is a sectional view of the operating head of the tube expandingtool of the present invention.

Before explaining the present invention in detail, it is to beunderstood that the invention is not limited in its application to thedetails of construction and arrangement of parts illustrated in theaccompanying drawings, since the invention is capable of otherembodiments and of being practiced or carried out in various ways. Also,it is to be understood that the phraseology or terminology employedherein is for the purpose of description and not of limitation.

Referring to the drawings, a heat exchange unit of the general type usedwith air conditioners is indicated at 10. The unit comprises a sinuoustubular heat exchange member composed of a series of hairpin tubes 12coupled together with U-shaped couplings 14. A heating or cooling mediumis passed through this tubular heat exchange member. A plurality of fins16 are disposed over the tubes 12 and have suitable openings therein toaccommodate said tubes.

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- especially when air is moved over the tubes since such moving air willset up vibration in the fins if they are loose with resultingundesirable noise.

The tube expanding tool of the present invention is used to securelyfasten the fins to the tubes. The tool is shown in detail in Fig. 3. Itcomprises a head 18 having a bullet-shaped nose 20 and a hammeringcollar 22. In a suitable tool now in use the diameter of the head is.010 inch smaller than the inside diameter of the tube to be expanded,and the diameter of the hammering collar is such as to provide thedesired diameter in the expanded tube.

The head 18 is provided with a chamber 24 having a tapered end portion26. A spindle 28 extends into the chamber 24 and is sufficiently smallerin diameter than the chamber to provide substantial clearance. Thespindle 28 has a tapered end portion 30. In use, a 58 degree taper at 26and a 60 degree taper at 30 have proven satisfactory. This difference inangle and the clearance between the spindle 28 and the wall of chamber24 cause the head 18 to produce a hammer eifect which will be explainedat a later point.

A pair of keys or keepers 32 and 34 extend from the head 18 into slots36 and 38 in the spindle 28 to prevent accidental removal of the spindlefrom the head. A flexible shaft 40 is alfixed to the spindle 28. Theshaft 41} can be of any desired length and is provided with suitablemeans for affixing it to a device such as an airoperated rivetinghammer.

The tool is shown in operation in Fig. 2. As the airoperated rivetinghammer is actuated, the head 18 is moved on the spindle due to thedifierent tapers 26 and 30 (Fig. 3) and the clearance between thespindle 28 and the Wall of chamber 24. This motion of the head poundsthe hammering collar 22 against the sidewall of the tube and expands thetube to the desired diameter. This expansion moves the tube 12 intotight engagement with the fin 16.

The collar 22 on head 18 actually produces a hammering effect whichpermanently expands the tube material. This permits easy operation andwithdrawal of the hammer since there is no spring-back of the tube. Thisfeature also permits the tool to be used with a hairpinshaped tube. Inthis manner, couplings 14 (Fig. 1) need be supplied at only one end ofadjacent tubes. It is not necessary to use straight tubes with couplingsat both ends.

The tube expanding tool of the present invention has proven that it willhammer tubes to fins securely and evenly to provide optimum efficiencyand strength.

Having thus described my invention, I claim:

A tube-expanding tool for use in expanding the diameter of a tube alongits entire length or any portion thereof comprising a head having ablind chamber therein, a conical surface forming the blind end of saidchamber, a spindle having one end extending into said chamber, saidspindle being substantially smaller in diameter than said chamber toprovide a substantial clearance between said head and said spindle, aconically tapered surface formed on the end of said spindle which has anincluded angle greater than the included angle of the aforementionedconical surface and which lies adjacent thereto, and a hammering collaron said head near the front thereof, movement of said spindle causingsaid head to (References on following page) Rfe'renes Cited in the file'of this patent 1,004,617 Archer Oct. 3, 19 V 1,727,915 Tli'omson Sept.10, 192 9 UNITED STATESPATENTS 2,459,808 Geyer Jan. 25, 1949 175,316WinQrcL A ..Mar\.2 ,8,,18 76 2,493,127 Franck Jan. 3, 1950 848, 459""G'rant' Ma13.26,}1907 5 2,526,210 Edelmann Oct. 17, 1950

